1. Field of the Invention
This invention relates generally to temperature control for an electronic device, and, more particularly, to a heat sink for cooling an electronic device.
2. Description of the Related Art
Heat sinks have been widely used to cool electronic devices. Generally, a heat sink operates in a convective heat transfer mode. The heat dissipation ability of the heat sink is directly proportional to its surface area. A common technique for cooling an electronic device is to provide a metal plate on a surface of the device package and mount a heat sink to the metal plate. The metal plate provides a conductive pathway between a die contained within the device package and the heat sink. The thermal efficiency of the coupling from the die to the heat sink greatly affects the ability of the heat sink to cool the die.
In many cases, the cost of the cooling means (e.g., the heat sink) plays a significant role in determining the overall cost of an electronic device. A manufacturer using electronic devices in bulk can appreciate a large savings in terms of tooling and manufacturing costs if the heat sink design can be simplified.
Referring to FIG. 1, a prior art heat sink 10 is shown. The heat sink 10 includes a plurality of rectangular folds 12. The heat sink 10 is coupled to a device package 14 containing a die 16. A metal plate 18 is provided between the heat sink 10 and the device package 14. The heat sink 10 clips on to the device package 14. Detents 20 formed in the device package 14 interface with feet 22 of the heat sink 10 to provide the connection.
This configuration poses several problems. First, the rectangular folds 12 are not centered about the die 16, thus reducing the efficiency of the heat transfer between the die 16 and the heat sink 10. Second, the device package is more costly to manufacture due to the need to provide the detents 20 for interfacing with the feet 22.
A third problem is that because the heat sink 10 is attached to the device package 14, the possible configurations of the device package 14 are limited, and thus the flexibility of the heat sink 10 is also limited. Because the detents 20 are located on two of the sides of the device package 14, the heat sink 10 may only be used with a device package 14 having pins 24 on two sides. In other words, the heat sink 10 cannot be used with commonly used packages (not shown) having pins on all four sides. Also, if the dimensions of the device package 14 change, the heat sink 10 must be redesigned to provide the proper interface. These items limit the application of a particular heat sink design to a particular package design, in that any changes in the package 14 would require design and tooling changes for the heat sink 10. Accordingly, changes in the device package 14 result in costly changes to the heat sink 10.
The present invention is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.